 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.core.internal.commands.util;

 /**
  * Used to sanity check runtime conditions. Assertion failures typically occur
  * when something is being misused, such as calling a method with illegal
  * arguments. Runtime exceptions are thrown. Once an assertion failure occurs,
  * further behavior is unspecified.
  *
  * @since 3.1
  */
 public final class Assert {

     /**
      * Asserts that the given object is not <code>null</code>. If this is not
      * the case, some kind of unchecked exception is thrown.
      *
      * @param object
      * the value to test
      * @exception IllegalArgumentException
      * if the object is <code>null</code>
      */
     public static void isNotNull(Object object) {
         isNotNull(object, ""); //$NON-NLS-1$
 }

     /**
      * Asserts that the given object is not <code>null</code>. If this is not
      * the case, some kind of unchecked exception is thrown. The given message
      * is included in that exception, to aid debugging.
      *
      * @param object
      * the value to test
      * @param message
      * the message to include in the exception
      * @exception IllegalArgumentException
      * if the object is <code>null</code>
      */
     public static void isNotNull(Object object, String message) {
         if (object == null)
             throw new IllegalArgumentException ("null argument:" + message); //$NON-NLS-1$
 }

     /**
      * Asserts that the given expression is true. If this is not the case, some
      * kind of unchecked exception is thrown.
      *
      * @param expression
      * the expression to test
      * @return <code>true</code> if the expression is true.
      * @exception IllegalArgumentException
      * if the expression is not true
      */
     public static boolean isTrue(boolean expression) {
         return isTrue(expression, ""); //$NON-NLS-1$
 }

     /**
      * Asserts that the given expression is true. If this is not the case, some
      * kind of unchecked exception is thrown. The given message is included in
      * that exception, to aid debugging.
      *
      * @param expression
      * the expression to test
      * @param message
      * the message to include in the exception
      * @return <code>true</code> if the expression is true.
      *
      * @exception IllegalArgumentException
      * if the expression is not true
      */
     public static boolean isTrue(boolean expression, String message) {
         if (!expression)
             throw new IllegalArgumentException ("assertion failed:" + message); //$NON-NLS-1$
 return expression;
     }

     private Assert() {
         // This class should not be instantiated.
 }
 }

